1. Field of the Invention
The present invention relates to a laminated piezoelectric/electrostrictive element having a structure in which a piezoelectric/electrostrictive layer and electrode layers are stacked in an interdigitating comb-shaped pattern, a method of manufacturing the piezoelectric/electrostrictive element, a piezoelectric/electrostrictive device having the above laminated piezoelectric/electrostrictive element, and a method of manufacturing the piezoelectric/electrostrictive device.
2. Description of the Related Art
A piezoelectric/electrostrictive device such as an actuator element or a sensor element using a piezoelectric/electrostrictive layer is produced as follows. A wiring pattern made of a first electrode layer is formed on a ceramic substrate by printing, for example. A piezoelectric/electrostrictive layer is further formed thereon by printing, followed by sintering to fix the layer. After that, a wiring pattern made of another electrode layer is formed.
The piezoelectric/electrostrictive device can be used as an actuator element in which an electric field is applied to the piezoelectric/electrostrictive layer by supplying an electric signal to the wiring pattern so that the piezoelectric/electrostrictive layer is consequently displaced. The device also can be used as a sensor element. In the sensor element, an electric signal generated depending on the pressure applied to the piezoelectric/electrostrictive layer is outputted from the wiring pattern (see, for example, Japanese Laid-Open Patent Publication No. 2001-210887).
The process of manufacturing such a piezoelectric/electrostrictive device includes a cutting step of cutting a workpiece with a diamond cutter or the like in order to produce a number of pieces and remove unwanted portions.
In the cutting process, since the piezoelectric/electrostrictive layer and the ceramic substrate is of high hardness, they can be severed neatly along cutting lines. However, the electrode layer contains a metal that is lower in hardness than ceramics, and hence it is difficult to sever the electrode layer neatly along cutting lines, tending to leave burrs.
When a voltage is applied to the electrode layer, an electric discharge is liable to occur at the tip end of a burr. The electric discharge causes an excessive current to flow, or its plasma tends to break a portion of the piezoelectric/electrostrictive layer. If the burr is too long, it may cause a short-circuit between electrode layers that face each other.
For solving the above problem, it is necessary to remove the burrs that have been produced. Deburring processes include a process of polishing cut surfaces of the piezoelectric/electrostrictive device and a process of selectively etching a portion of the electrode layer.
However, the polishing process is apt to increase the manufacturing cost. The etching process is problematic in that if the electrode material is a corrosion-resistant metal such as platinum, then it is difficult to etch the electrode material.